It depends on the amount of effort required and the impact of what's being discussed. I'm not going to argue with people that grass is green, or the earth is round. SM started to engage in politics in the mid 20th century, and I even provided some examples of topics they've covered in that period. They then got pissy and demanded evidence, which in the context of what's being discussed, is a dick move. So, I told him where to get off.

In cases where the discussion is actually important, such as anthropogenic climate change for example, or issues with Test-Driven Development, I provide the receipts.